What the *hell* was John going on about in class, with regards to this picture?

I think the best way to color it would require doing knockouts of most of the black areas (i.e. converting them to color in Photoshop), leaving a minimum of black (just the main outlines of the figure, staff, and ground). Speaking expertly as your former colorist, of course

Though tarot purists might get mad that some of the stuff isn't int he pic, it's still sweet none the less. The proportions of tarot cards are always very cool. And your penwork in this just kicks, kid!